To better understand effects of climate change on children's health, we propose to: (1) Develop high-resolution spatial and temporal models that will enable us to estimate neighborhood-specific ground-level ozone and surface temperature levels, and (2) Link these estimated exposures to population-based data on childhood asthma hospitalizations and pediatric emergency department visits geo-coded to residential zip-code. We hypothesize that children are particularly vulnerable and that health effects of climate change will be magnified in socially disadvantaged communities. An impediment to previous study of these issues has been lack of high- resolution data on ozone and temperature levels. We propose to overcome this limitation by constructing spatially and temporally resolved estimates of surface temperature, heat index, and air pollution at the neighborhood level using rich datasets collected through atmospheric monitoring networks in New York City (NYC) and interpolated to the community level using sophisticated local climate models. This study builds upon the unique highly-spatially resolved data and analytic infrastructure of the NYC Community Air Survey and existing models to predict future temperature increases to examine the potential for climate change to produce varying impacts on health city-wide. No study has used such a highly spatially-resolved database as proposed here. Further, we employ a unique previously-compiled dataset of city-wide susceptibility indicators to understand community-level vulnerability to climate change by chronic stressors. Specific Aim 1: Develop fine-grained, neighborhood-specific, spatially and temporally resolved calculations of ground-level ozone and surface temperature levels in multiple, highly diverse communities across the five boroughs of NYC. Specific Aim 2: Conduct an epidemiologic analysis of child health outcomes in multiple, diverse NYC communities during warm summer weather. Results of this research will be shared with city agencies to inform near-term climate adaptation as well as ongoing efforts to incorporate climate risk information into long term plans concerning land use, infrastructure, and other climate change adaptation measures. This research will provide pilot data to larger projects currently being developed in Pittsburgh. Developing stronger methods to assess short-term intra-urban variation in temperature and air pollution on children's health outcomes will enable improved assessment of children's health in other cities as well as different vulnerable age groups in NYC.